22 Belt drive parts are listed for the 2021 Freightliner MT, in 2 part types, covering all 3 engine options (5.1L L4 DIESEL Turbocharged, 6.0L V8 and 6.7L L6 DIESEL Turbocharged). Each one has a brand, a manufacturer part number and notes that say where it fits.
On the 2021 Freightliner MT, the belt drive system spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys. All 22 listed parts are Belt (17 parts) and Belt Tensioner (5 parts).
The 2021 Freightliner MT was sold with 3 engines. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 Freightliner MT belt drive parts are GATES (8 parts), DAYCO (5 parts) and ACDELCO (4 parts), plus 3 more brands. Quality grades include Standard Replacement, Heavy Duty and Economy.
5 parts on this 2021 Freightliner MT page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including GATES K060984 (Belt) and GATES 38702 (Belt Tensioner). Click any part number to see every vehicle that part fits.
Belt
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 6.0L V8 | K060984 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| ROADMAX Popular Fits: 6.0L V8 | 6K984AP | 🇺🇸 US 🇨🇦 CA | V-RibbedSerpentine | View on Amazon |
| DAYCO Fits: 6.0L V8 | 5060985DR | 🇺🇸 US 🇨🇦 CA | Drive Rite®Serpentine | View on Amazon |
| ROADMAX Fits: 6.7L L6 DIESEL Turbocharged | 8K830AP | 🇺🇸 US 🇨🇦 CA | V-RibbedSerpentine | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 6.7L L6 DIESEL Turbocharged | K080830HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| ACDELCO Fits: 6.7L L6 DIESEL Turbocharged | K080830HD | 🇺🇸 US 🇨🇦 CA | Professional / GoldHeavy Duty | View on Amazon |
| CONTINENTAL Fits: 6.7L L6 DIESEL Turbocharged | 4080830X | 🇺🇸 US 🇨🇦 CA | Extreme Duty Multi V-BeltSerpentine | View on Amazon |
| GATES Fits: 5.1L L4 DIESEL Turbocharged | K080708HD | 🇺🇸 US | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Fits: 6.0L V8 | K060984HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
High Performance
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 5080830SC | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 6.7L L6 DIESEL Turbocharged | K080830 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| ACDELCO Fits: 5.1L L4 DIESEL Turbocharged | 8K708 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| ACDELCO Fits: 6.0L V8 | 6K984 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| ACDELCO Fits: 6.7L L6 DIESEL Turbocharged | 8K830 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| DAYCO Fits: 6.0L V8 | 5060985 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 5080830 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| GATES Fits: 5.1L L4 DIESEL Turbocharged | K080708 | 🇺🇸 US | Micro-V | View on Amazon |
This table covers the serpentine and accessory belts that drive the front accessories. Typical signs include squeal on cold start, cracks across the ribs, or glazing on the back of the belt. A new belt on a worn tensioner will squeal within weeks — spin the idlers by hand while the belt is off.
17 Belt parts are listed for the 2021 Freightliner MT, from GATES, DAYCO, ACDELCO and 2 other brands. GATES K060984 carries the "Popular" badge.
In the Economy grade, ROADMAX, GATES and DAYCO supply 4 parts: the catalog's value-priced group. A representative part number is GATES K060984.
The Heavy Duty section lists 5 options from GATES, ACDELCO and CONTINENTAL — rated for severe service. GATES K080830HD is listed in this group.
In the High Performance grade, DAYCO supplies 1 part: engineered beyond original-equipment specification. A representative part number is DAYCO 5080830SC.
The Standard Replacement section lists 7 options from ACDELCO, GATES and DAYCO — built to original-equipment specification. GATES K080830 is listed in this group.
Belt Tensioner
Kit
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 6.7L L6 DIESEL Turbocharged | 90K38702HDC | 🇺🇸 US 🇨🇦 CA | Heavy DutyKit | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 6.7L L6 DIESEL Turbocharged | 38702 | 🇺🇸 US 🇨🇦 CA | Fleet Runner | View on Amazon |
| CONTINENTAL Fits: 6.7L L6 DIESEL Turbocharged | 49607 | 🇺🇸 US 🇨🇦 CA | Multi-V | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 89930 | 🇺🇸 US 🇨🇦 CA | Air Conditioning, Alternator and Water PumpMT45 | View on Amazon |
| LITENS Fits: 6.7L L6 DIESEL Turbocharged | 910588A | 🇺🇸 US 🇨🇦 CA | Air Conditioning, Alternator, Fan and Water Pump | View on Amazon |
This table covers the automatic tensioners that hold belt tension. Typical signs include belt flutter, a chirp that returns after a new belt, or a damper that no longer holds the arm. Replace the tensioner with the belt at higher mileage; the labor overlaps almost entirely.
5 Belt Tensioner parts for the 2021 Freightliner MT come from 4 brands — GATES, CONTINENTAL, DAYCO and 1 other brand. The "Popular" part is GATES 38702.
The Kit section lists 1 option from GATES — grouped under the catalog's "Kit" designation — the notes column spells out what sets them apart. GATES 90K38702HDC is listed in this group.
Standard Replacement: 4 parts, from GATES, CONTINENTAL, DAYCO and 1 other brand. A representative part number is GATES 38702.
This group includes GATES 38702, GATES 90K38702HDC and CONTINENTAL 49607 and the remaining parts above.
Buying Belt Drive Parts for a 2021 Freightliner MT
On this vehicle, the belt drive system spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys.
- Match the engine first. Every belt drive part here is engine-specific; each row shows which engine(s) it fits.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Belt and Belt Tensioner .
Frequently Asked Questions
How many belt drive parts fit the 2021 Freightliner MT?
Our catalog currently lists 22 belt drive parts for the 2021 Freightliner MT across 2 subcategories and 6 brands, covering all 3 engine options (5.1L L4 DIESEL Turbocharged, 6.0L V8 and 6.7L L6 DIESEL Turbocharged). Each part is matched to the engine(s) it fits.
Do belt drive parts differ between 2021 Freightliner MT engines?
Yes. Every belt drive part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of belt drive problems on a 2021 Freightliner MT?
Common symptoms include squealing on cold start, a belt that shows cracking or glazing, or an accessory that slows under load. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Freightliner MT was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Freightliner MT?
First match the engine — each row shows which engine(s) the part fits. Then a new belt on a worn tensioner will squeal within weeks — check tensioner damping and idler bearings while the belt is off. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Freightliner MT
Belt Drive Parts for Other Freightliner MT Years
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